/* -*-mode:java; c-basic-offset:2; -*- */
/*
Copyright (c) 2000,2001,2002,2003 ymnk, JCraft,Inc. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice,
     this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright 
     notice, this list of conditions and the following disclaimer in 
     the documentation and/or other materials provided with the distribution.

  3. The names of the authors may not be used to endorse or promote products
     derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JCRAFT,
INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 * This program is based on zlib-1.1.3, so all credit should go authors
 * Jean-loup Gailly(jloup@gzip.org) and Mark Adler(madler@alumni.caltech.edu)
 * and contributors of zlib.
 */

namespace com.jcraft.jzlib{

    internal sealed class Inflate{
  
      private const int MAX_WBITS=15; // 32K LZ77 window

      // preset dictionary flag in zlib header
      private const int PRESET_DICT=0x20;

      internal const int Z_NO_FLUSH=0;
      internal const int Z_PARTIAL_FLUSH=1;
      internal const int Z_SYNC_FLUSH=2;
      internal const int Z_FULL_FLUSH=3;
      internal const int Z_FINISH=4;

      private const int Z_DEFLATED=8;

      private const int Z_OK=0;
      private const int Z_STREAM_END=1;
      private const int Z_NEED_DICT=2;
      private const int Z_ERRNO=-1;
      private const int Z_STREAM_ERROR=-2;
      private const int Z_DATA_ERROR=-3;
      private const int Z_MEM_ERROR=-4;
      private const int Z_BUF_ERROR=-5;
      private const int Z_VERSION_ERROR=-6;

      private const int METHOD=0;   // waiting for method byte
      private const int FLAG=1;     // waiting for flag byte
      private const int DICT4=2;    // four dictionary check bytes to go
      private const int DICT3=3;    // three dictionary check bytes to go
      private const int DICT2=4;    // two dictionary check bytes to go
      private const int DICT1=5;    // one dictionary check byte to go
      private const int DICT0=6;    // waiting for inflateSetDictionary
      private const int BLOCKS=7;   // decompressing blocks
      private const int CHECK4=8;   // four check bytes to go
      private const int CHECK3=9;   // three check bytes to go
      private const int CHECK2=10;  // two check bytes to go
      private const int CHECK1=11;  // one check byte to go
      private const int DONE=12;    // finished check, done
      private const int BAD=13;     // got an error--stay here

      int mode;                            // current inflate mode

      // mode dependent information
      int method;        // if FLAGS, method byte

      // if CHECK, check values to compare
      long[] was=new long[1] ; // computed check value
      long need;               // stream check value

      // if BAD, inflateSync's marker bytes count
      int marker;

      // mode independent information
      int  nowrap;          // flag for no wrapper
      int wbits;            // log2(window size)  (8..15, defaults to 15)

      InfBlocks blocks;     // current inflate_blocks state

      int inflateReset(ZStream z){
        if(z == null || z.istate == null) return Z_STREAM_ERROR;
    
        z.total_in = z.total_out = 0;
        z.msg = null;
        z.istate.mode = z.istate.nowrap!=0 ? BLOCKS : METHOD;
        z.istate.blocks.reset(z, null);
        return Z_OK;
      }

      internal int inflateEnd(ZStream z){
        if(blocks != null)
          blocks.free(z);
        blocks=null;
        //    ZFREE(z, z->state);
        return Z_OK;
      }

      internal int inflateInit(ZStream z, int w){
        z.msg = null;
        blocks = null;

        // handle undocumented nowrap option (no zlib header or check)
        nowrap = 0;
        if(w < 0){
          w = - w;
          nowrap = 1;
        }

        // set window size
        if(w<8 ||w>15){
          inflateEnd(z);
          return Z_STREAM_ERROR;
        }
        wbits=w;

        z.istate.blocks=new InfBlocks(z, 
                      z.istate.nowrap!=0 ? null : this,
                      1<<w);

        // reset state
        inflateReset(z);
        return Z_OK;
      }

      internal int inflate(ZStream z, int f){
        int r;
        int b;

        if(z == null || z.istate == null || z.next_in == null)
          return Z_STREAM_ERROR;
        f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
        r = Z_BUF_ERROR;
        while (true){
    //System.out.println("mode: "+z.istate.mode);
          switch (z.istate.mode){
          case METHOD:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            if(((z.istate.method = z.next_in[z.next_in_index++])&0xf)!=Z_DEFLATED){
              z.istate.mode = BAD;
              z.msg="unknown compression method";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }
            if((z.istate.method>>4)+8>z.istate.wbits){
              z.istate.mode = BAD;
              z.msg="invalid window size";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }
            z.istate.mode=FLAG;
          #region copy of FLAG

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            b = (z.next_in[z.next_in_index++])&0xff;

            if((((z.istate.method << 8)+b) % 31)!=0){
              z.istate.mode = BAD;
              z.msg = "incorrect header check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            if((b&PRESET_DICT)==0){
              z.istate.mode = BLOCKS;
              break;
            }
            z.istate.mode = DICT4;
          #region copy of DICT4

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need=((z.next_in[z.next_in_index++]&0xff)<<24)&0xff000000L;
            z.istate.mode=DICT3;
          #region copy of DICT3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode=DICT2;
          #region copy of DICT2

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode=DICT1;
          #region copy of DICT1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need += (z.next_in[z.next_in_index++]&0xffL);
            z.adler = z.istate.need;
            z.istate.mode = DICT0;
            return Z_NEED_DICT;
          #endregion
          #endregion
          #endregion
          #endregion
          #endregion
          case FLAG:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            b = (z.next_in[z.next_in_index++])&0xff;

            if((((z.istate.method << 8)+b) % 31)!=0){
              z.istate.mode = BAD;
              z.msg = "incorrect header check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            if((b&PRESET_DICT)==0){
              z.istate.mode = BLOCKS;
              break;
            }
            z.istate.mode = DICT4;
          #region copy of DICT4

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need=((z.next_in[z.next_in_index++]&0xff)<<24)&0xff000000L;
            z.istate.mode=DICT3;
          #region copy of DICT3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode=DICT2;
          #region copy of DICT2

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode=DICT1;
          #region copy of DICT1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need += (z.next_in[z.next_in_index++]&0xffL);
            z.adler = z.istate.need;
            z.istate.mode = DICT0;
            return Z_NEED_DICT;
          #endregion
          #endregion
          #endregion
          #endregion
          case DICT4:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need=((z.next_in[z.next_in_index++]&0xff)<<24)&0xff000000L;
            z.istate.mode=DICT3;
          #region copy of DICT3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode=DICT2;
          #region copy of DICT2

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode=DICT1;
          #region copy of DICT1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need += (z.next_in[z.next_in_index++]&0xffL);
            z.adler = z.istate.need;
            z.istate.mode = DICT0;
            return Z_NEED_DICT;
          #endregion
          #endregion
          #endregion
          case DICT3:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode=DICT2;
          #region copy of DICT2

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode=DICT1;
          #region copy of DICT1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need += (z.next_in[z.next_in_index++]&0xffL);
            z.adler = z.istate.need;
            z.istate.mode = DICT0;
            return Z_NEED_DICT;
          #endregion
          #endregion
          case DICT2:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode=DICT1;
          #region copy of DICT1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need += (z.next_in[z.next_in_index++]&0xffL);
            z.adler = z.istate.need;
            z.istate.mode = DICT0;
            return Z_NEED_DICT;
          #endregion
          case DICT1:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need += (z.next_in[z.next_in_index++]&0xffL);
            z.adler = z.istate.need;
            z.istate.mode = DICT0;
            return Z_NEED_DICT;
          case DICT0:
            z.istate.mode = BAD;
            z.msg = "need dictionary";
            z.istate.marker = 0;       // can try inflateSync
            return Z_STREAM_ERROR;
          case BLOCKS:

            r = z.istate.blocks.proc(z, r);
            if(r == Z_DATA_ERROR){
              z.istate.mode = BAD;
              z.istate.marker = 0;     // can try inflateSync
              break;
            }
            if(r == Z_OK){
              r = f;
            }
            if(r != Z_STREAM_END){
              return r;
            }
            r = f;
            z.istate.blocks.reset(z, z.istate.was);
            if(z.istate.nowrap!=0){
              z.istate.mode=DONE;
              break;
            }
            z.istate.mode=CHECK4;
          #region copy of CHECK4

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need=((z.next_in[z.next_in_index++]&0xff)<<24)&0xff000000L;
            z.istate.mode=CHECK3;
          #region copy of CHECK3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode = CHECK2;
          #region copy of CHECK3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode = CHECK1;
          #region copy of CHECK1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=(z.next_in[z.next_in_index++]&0xffL);

            if(((int)(z.istate.was[0])) != ((int)(z.istate.need))){
              z.istate.mode = BAD;
              z.msg = "incorrect data check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            z.istate.mode = DONE;
          #region copy of DONE
            return Z_STREAM_END;
          #endregion
          #endregion
          #endregion
          #endregion
          #endregion
          case CHECK4:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need=((z.next_in[z.next_in_index++]&0xff)<<24)&0xff000000L;
            z.istate.mode=CHECK3;
          #region copy of CHECK3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode = CHECK2;
          #region copy of CHECK3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode = CHECK1;
          #region copy of CHECK1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=(z.next_in[z.next_in_index++]&0xffL);

            if(((int)(z.istate.was[0])) != ((int)(z.istate.need))){
              z.istate.mode = BAD;
              z.msg = "incorrect data check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            z.istate.mode = DONE;
          #region copy of DONE
            return Z_STREAM_END;
          #endregion
          #endregion
          #endregion
          #endregion
          case CHECK3:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<16)&0xff0000L;
            z.istate.mode = CHECK2;
          #region copy of CHECK3

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode = CHECK1;
          #region copy of CHECK1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=(z.next_in[z.next_in_index++]&0xffL);

            if(((int)(z.istate.was[0])) != ((int)(z.istate.need))){
              z.istate.mode = BAD;
              z.msg = "incorrect data check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            z.istate.mode = DONE;
          #region copy of DONE
            return Z_STREAM_END;
          #endregion
          #endregion
          #endregion
          case CHECK2:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=((z.next_in[z.next_in_index++]&0xff)<<8)&0xff00L;
            z.istate.mode = CHECK1;
          #region copy of CHECK1

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=(z.next_in[z.next_in_index++]&0xffL);

            if(((int)(z.istate.was[0])) != ((int)(z.istate.need))){
              z.istate.mode = BAD;
              z.msg = "incorrect data check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            z.istate.mode = DONE;
          #region copy of DONE
            return Z_STREAM_END;
          #endregion
          #endregion
          case CHECK1:

            if(z.avail_in==0)return r;r=f;

            z.avail_in--; z.total_in++;
            z.istate.need+=(z.next_in[z.next_in_index++]&0xffL);

            if(((int)(z.istate.was[0])) != ((int)(z.istate.need))){
              z.istate.mode = BAD;
              z.msg = "incorrect data check";
              z.istate.marker = 5;       // can't try inflateSync
              break;
            }

            z.istate.mode = DONE;
          #region copy of DONE
            return Z_STREAM_END;
          #endregion
          case DONE:
            return Z_STREAM_END;
          case BAD:
            return Z_DATA_ERROR;
          default:
            return Z_STREAM_ERROR;
          }
        }
      }


      internal int inflateSetDictionary(ZStream z, byte[] dictionary, int dictLength){
        int index=0;
        int length = dictLength;
        if(z==null || z.istate == null|| z.istate.mode != DICT0)
          return Z_STREAM_ERROR;

        if(z._adler.adler32(1L, dictionary, 0, dictLength)!=z.adler){
          return Z_DATA_ERROR;
        }

        z.adler = z._adler.adler32(0, null, 0, 0);

        if(length >= (1<<z.istate.wbits)){
          length = (1<<z.istate.wbits)-1;
          index=dictLength - length;
        }
        z.istate.blocks.set_dictionary(dictionary, index, length);
        z.istate.mode = BLOCKS;
        return Z_OK;
      }

      static private byte[] mark = {(byte)0, (byte)0, (byte)0xff, (byte)0xff};

      internal int inflateSync(ZStream z){
        int n;       // number of bytes to look at
        int p;       // pointer to bytes
        int m;       // number of marker bytes found in a row
        long r, w;   // temporaries to save total_in and total_out

        // set up
        if(z == null || z.istate == null)
          return Z_STREAM_ERROR;
        if(z.istate.mode != BAD){
          z.istate.mode = BAD;
          z.istate.marker = 0;
        }
        if((n=z.avail_in)==0)
          return Z_BUF_ERROR;
        p=z.next_in_index;
        m=z.istate.marker;

        // search
        while (n!=0 && m < 4){
          if(z.next_in[p] == mark[m]){
            m++;
          }
          else if(z.next_in[p]!=0){
            m = 0;
          }
          else{
            m = 4 - m;
          }
          p++; n--;
        }

        // restore
        z.total_in += p-z.next_in_index;
        z.next_in_index = p;
        z.avail_in = n;
        z.istate.marker = m;

        // return no joy or set up to restart on a new block
        if(m != 4){
          return Z_DATA_ERROR;
        }
        r=z.total_in;  w=z.total_out;
        inflateReset(z);
        z.total_in=r;  z.total_out = w;
        z.istate.mode = BLOCKS;
        return Z_OK;
      }

      // Returns true if inflate is currently at the end of a block generated
      // by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
      // implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
      // but removes the length bytes of the resulting empty stored block. When
      // decompressing, PPP checks that at the end of input packet, inflate is
      // waiting for these length bytes.
      int inflateSyncPoint(ZStream z){
        if(z == null || z.istate == null || z.istate.blocks == null)
          return Z_STREAM_ERROR;
        return z.istate.blocks.sync_point();
      }
    }
}